1. Field of the Invention
The present invention relates to a pneumatic tire with a noise damper for reducing a road noise, and more particularly to improve its uniformity.
2. Description of the Related Art
A road noise is known as one of tire noises. The road noise is a sound around from 50 to 400 Hz generated from a tire running on a road. A main cause of the road noise is resonance vibrations of air generated in the tire cavity. In recent years, there is proposed a pneumatic tire which comprises a main body c and a noise damper (a) made of spongy material and attached to the inner surface of the tread portion d of the main body c as shown in FIG. 10.
The noise damper is preferably pre-formed into an annular body and is inserted into the tire cavity to attach onto an inner surface thereof. However, since such a method requires preparing many kinds of noise dampers and molds to form them in accordance with each size of the tire, a productivity of the tire deteriorates remarkably.
Therefore, a noise damper having a non-annular body is proposed. The noise damper is made by bending a sheet-like sponge into an arc along the inner surface of the main body c. However, such a noise damper has a gap part causing a deterioration of a uniformity of the tire between ends thereof.